Voxengo's Soniformer 2.2 is a mastering tool that adds M/S encoding of L/R stereo signals into middle and side channels, which can then be compressed or expanded as needed.

After processing is performed, the M/S signal is converted into a L/R signal. Additional features include spectral compression, gain-change meters, 32-band spectrum analysis, two level-detector types, mono-to-stereo processing and up to 192kHz sample rate support.